1. Field of the Invention
The invention relates to a vehicle night vision support system that displays an image, captured in the nighttime by an infrared camera mounted on a vehicle, on an in-vehicle display, or the like, so that the captured image can be visually recognized in a vehicle cabin, and a control method for the same.
2. Description of the Related Art
There is known an existing system in which an infrared camera that is able to, for example, recognize a pedestrian even in the nighttime captures an image and then the captured image is displayed in a vehicle cabin.
In relation to this, Japanese Patent Application Publication No. 2005-081860 (JP-A-2005-081860) describes a vehicle display system. The vehicle display system includes a driving environment detecting means that detects a driving environment ahead of a vehicle, and changes an area captured by an image capturing means, such as an infrared camera, into a wide angle depending on the detected driving environment. The vehicle display system detects, for example, the presence of a preceding vehicle as the driving environment ahead of the vehicle, and changes the captured area into a wide angle when there is the preceding vehicle.
In addition, Japanese Patent Application Publication No. 2005-088630 (JP-A-2005-088630) describes a vehicle night vision system. The vehicle night vision system swivels an image capturing means, such as an infrared camera, horizontally in a vehicle transverse direction on the basis of a steering angle signal detected by a steering angle sensor. Note that the image capturing means is swiveled horizontally in the vehicle transverse direction in synchronization with head lights.
Incidentally, an image captured by the infrared camera is displayed on a display device (which is also used for, for example, a navigation display) installed at the center portion of an instrument panel, or the like, or is displayed on a head up display (HUD). The HUD is a display device that, for example, reflects light, emitted from a light-emitting device installed at the upper portion of the instrument panel, from a front glass to allow a driver to visually recognize the emitted light.
Then, there has been proceeding toward commercialization of a system that supports vision of a driver on the basis of an image captured by an infrared camera using such a plurality of display devices. In this system, an image captured by an infrared camera is, for example, displayed on a main display installed at the center portion of an instrument panel, or the like, and warning information, such as an icon that indicates the shape of an object, is displayed on a sub-display, such as an HUD, when the displayed image contains a warning target object, such as a pedestrian.
However, according to the existing systems, the driver may experience a feeling of strangeness because of a difference between the angle of view of the infrared camera and the field of view of the driver.
The angle of view of the infrared camera is normally narrower than the field of view of a driver in consideration of a resolution, a requirement for capturing an image at a location farther from the illumination limit of the head lamps, and the like. This is because the accuracy of remote image capturing decreases when the image capturing range is set to a wide angle.
Thus, in the process in which an object ahead of the vehicle approaches the vehicle and then passes by the vehicle to behind the vehicle, there is a period of time during which the driver visually recognizes the object although the object is not captured by the infrared camera (or is captured by the infrared camera but the object is located outside the display range). During the above period of time, the driver may experience a feeling of strangeness against a situation that the warning information of the sub-display disappears although the driver visually recognizes the pedestrian.
In addition, the situation that the object can be visually recognized by the driver still requires attention to the object when driving. Thus, when the warning information of the sub-display disappears, it may result in an insufficient support.